Hot-air furnace.



PATENTBDSEPT. 15, 1903. J. H. TUTTLE, Jn. HOT AIR PURNAGB.

APPLICATION FILED HAY 9, 1903.

N0 MODEL.

2 SHEETS-SHEET 1.

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, f f f TATBNTED SEPT. 15, .1903.

J. H. TUTTLE, JR. HOT ATR TURNACE.

APPLICATION FILED MAY 9, 1903.

2 SHEETS-SHEET 2l .N0 MODEL.

UNITED STATES Patented September 15, 1903.

PATENT GFFIGE.

HOT-AIR FU RNACE.

SPECIFICATION forming part of Letters Patent No. 739,036, dated September 15, 1903.

Application filed May 9,1903. Serial No. 156,351. (No model.)

to certain forms of heating-drums which are superimposed above the combustion-chamber and cold-air inlet.

IThe object of the special features hereinafter described is to introduce the cold air into the base of the furnace in a plane beheath the fire-pot and to cause the air to cir- 'culate aroundthe fire-box and to then pass upwardly between a pair of drums which are 'corrugated vertically, so that the upward passage of the air is somewhat impeded by being obliged to pass in zigzag paths from the lower air-receiving chamber to an upper distributing-chamber, the inner drum being closed at its upper end and provided with a lateral outlet or smoke-line, which connects the inner shell or drum with a smoke-chamber sur- 4rounding said outer drum.

Further objects will appear in the subsequent description.

In the drawings, Figure 1 is a transverse vertical sectional View through my improved furnace from front to rear. Fig. 2 is a horinontal sectionalview taken on line 2 2, Fig. 1. Figs. 3 and 4 are top plan views, respectively, of the upper and lower decks detached and 'reduced in size.

In carrying lout the objects of this invention I provide a suitable base 1, upon which is mounted an ash-box 2 and an outer inclosing shell or jacket 3, the ash-box 2 being extended through the front wall of the. outer shell 3 and is provided with the usual door 4 and grate 5.

Mounted upon the ash-box 2 and inclosing the grate 5 is a nre-box 6, which is preferably circular in cross-section and is arranged centrally within the shell 3, being of considerably less diameter than the shell for forming an air space or chamber 7, which entirely surrounds the vfire-box and extends around the rear and side walls of the ash-box, a suitable cold-air inlet 8 being formed in the rear wall of the shell-3 in a plane beneath the irebox and directly in the rear of the ash-box.

A horizontal deck 9 is supported upon the upper end of the fire-box and receives inner and outer corrugated shells or drums 10 and 11 and an additional outer shell 12, the upper ends of said shells 10, 11, and 12 being held invposition by an upper deck 13. The inner shell ordrum 10 is open at its lower end and communicates with the interior of the fire-pot 6, while its upper end is closed -by a dome-shaped wall 14, forming a part of the upper deck 13. The side walls of the shell 10 are corrugated vertically in such manner that the lower end flares outwardly, or rather tapers upwardly, whereby the heated products of combustion impinge directly against the overhanging portions or walls for the purpose of radiating as much heat as possible at the point of entrance ofthe air from the chamber 7 into the space between the sections 10 and 11, While the upper end of the shell 1 tapers inwardly toward the dome 14 for deiiecting the products of combustion inwardly and downwardly toward the center of the shell.

The intermediate corrugations are quite pronounced, so that the heated-products of combustion ascending from the combustionchamber are successively contracted and expanded in passing to the upper end of the shell. This form of interior shell aords a large area of the heating and radiating surface and the portions of the corrugations which incline inwardly and outwardly serve to impede the passage of the products of combustion to the outlet, and therefore aords a -more efcient radiating surface for heating the air which passes upwardly between the sections 10 and 11. v

The lower ends of the front wall of the shells 10, 11, and 12 are provided with openings for receiving a hollow frame 15,'through which the fuel is fed into the interior of the shell 10 and into the tire-pot 6, said frame extending outwardly through the shell 3, and is provided with a suitable door or closure 16. The

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upper ends of the corrugated shells and 11 are provided with openings for receiving a smoke-conduit 17, which may be cast integral with one of the sections, if desired, or may be formed separate from said sections and secured thereto by any form of fastening means to prevent the leakage of the gas from the interior of the shell 10 to the air-chamber between the sections 10 and 11.

The shell 11 is of greater diameter than the inner shell 10 and entirely surrounds the latter shell, being corrugated vertically for forming a tortuous air-passage 18, the lower end of which communicates with the chamber 7 through an opening 19 in the deck 9, and its upper end communicates with a distributingchamber 20 in the upper end of the shell 3 through an opening 21 in the upper deck.

The vertical corrugations of the outer shell follow the same corrugations in the inner shell, so that the projections of one section or shell are 'alined with the projections in the adjacent face of the other shell, and the inwardly-projecting ribs of the outer shell 11 are disposed in substantially vertical alinement with the outwardly-projecting ribs of the inner shell, whereby the air is caused to pass in zigzag paths from the chamber 7 into the distributing-chamber 20.

Leading from the interior of the shell 12 through the outer shell 3 are upperand lower smoke-fines 22 and 23, the upper smoke-liuc 22 being arranged in alinement with the iiue 17, and the lower conduit 23 is located in proximity to the lower deck 9, said conduits 22 and 23 being connected to a suitable smokestack or pipe 24. The shell l2 is of greater diameter than the extreme diameter of the corrugated shell 11 for forming a smokechamber 25, the opposite ends of which are closed by the lower and upper decks 9 and 13, so that the outer shell 11 is entirely surrounded by the smoke-chamber 25. This smoke-chamber 25 communicates with the interior of the shell 10 through the smoke-fine 17, and I usually provide a baille-plate 26, which is arranged horizontally between the shells 11 and 12 in a plane substantially midway between the smoke-conduits 22 and 23, the smoke-conduit 22 being provided with a damper 28.

It is now apparent that the product of combustion passing upwardly into the shell 10 is successively impinged against the inwardly and upwardlyinclined walls of the corrugated sides, and therefore causes the radiation of considerable heat into the air-space 1S, the smoke and gases being discharged through the smoke-flue 17, and when the chamber 28 is closed the-se products of combustion pass downwardly around the ends of the baftieplate 26 and outwardly through the lower smoke-conduit 23, while, on the other hand, when a direct draft is required the chamber 28 is open and the products of combustion pass readily from the flue 17 into the upper smoke-conduit 23 and thence into the main smoke-pipe 24.

The portions of the upper and lower decks 9 at the opposite sides of the air-passages 19 and 21 are connected by ribs or tie-bars 30, which are usually narrow and do not interfere in any way with the free passages of the air from the chamber 7 to the distributing-chamber 20, the latter chamber being provided with suitable outlet-openings 31, to which the distributing-pipes are connected.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

1. Inahot-airfurnace,thecombinationwith an ash-box having a grate-opening in its npper wall, a grate, a fire-pot resting upon and rising from the upper wall of the ash-box, a lower deck mounted upon and surrounding the upper end of the fire-pot and projecting laterally therefrom, an inner drum resting upon and rising from the deck over the lirepot, the upper end being closed and its side walls being corrugated vertically, a second drum surrounding the former drum and of greater diameter to form an air-space between the drums at the outside of the fire-box, an additional drum surroundingthesecond drum and of greater diameter than the latter to form a smoke-chamber, an upper deck connecting the upper ends of said drums and forming the end wall of the inner drum, a fuel-conduit in the front walls of the drums', and a smokeoutlet conduit leading from the interior of the inner drum through the second drum.

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2. In a hot-air furnace, an outer shell or jacket having an air-inlet in its baseand distributing-chamber in its upper end, a tire-pot centrally within the shell, a lower deck resting upon and surrounding the upper end of the lire-pot and projecting laterally therefrom, said deck having an air-passage communicating with the space surrounding the fire-pot, inner and outer drums resting on the deck at opposite sides of the air-passage and having their side walls corrugated vertically and separated from each other to form an airspace, a smoke-conduit connecting the side walls across the air-space, an additional drum surrounding the former drums and resting on said deck to form a smoke-chamber, said additionaldrum having lower and upper smokeoutlets, a baiiieplate between the outlets, and an upper deck covering the upper ends of the inner drum and smoke-chamber and having an airpassage connecting the airspace between the corrugated drums with the distributing-chamber.

3. In combination with a tire-pot, a lower deck resting on the fire-pot and having an airpassage communicating with the space surrounding said iire-pot, an inner drum resting npon and rising from the deck at the inside of the air-passage and having vertically-corrugated side walls, a second drum resting upon and rising from the deck at the outside of said passage, a third drum rising from the deck and surrounding the second drum, anv

upper deck mounted upon the upper ends of said drums and closing the upper end of the inner drum and also the space between the second and third drums and having an airpassage leading from the space between the first and second drums, a fuel-inlet conduit, 

